M3 airbox onto M20, rolling roaded today!

[d6dph]

Very interesting Simon. Nice to see a healthy gain too.
Well done.

[Jhonno]

Nice one Si.. Good to see its been properly looked at

[reggid]

what were the AFR's like between the two runs? Can you post the two graphs?

[Simon13]

fueling is all over the shop, i don't have a scanner so can't really post up a decent picture

it's mega lean low end and mega rich top end

[reggid]

fueling is all over the shop, i don't have a scanner so can't really post up a decent picture

it's mega lean low end and mega rich top end

how about between the two runs were there any trends e.g. was it overall a tad leaner or just oll over the shop on both setups?

[gareth]

not being funny but until your fueling is set up, you've not proved a lot!
the fueling on any engine needs to be tuned to suit the inlet restrictions and characteristics present on the engine. it may well be that the M3 airbox suits the badly set up fueling better than the OE one, but it's still less power than standard.

what's upsetting the fueling so badly? would it be worth setting it up properly on both airboxes independantly to get a proper comparison?

[Simon13]

the fueling is out due to a chip!

in my eyes if the fueling was better there would still be a gain

[gareth]

i'm sure in your eyes it is but from a purely scientific point of view, it's of no use whatsoever!

the ONLY way to compare properly is to set it up right with one airbox, then get a power run. then repeat for the other airbox. the fueling requirements will be different for each one.

[snoops]

how can you adjust the fueling?

[maxfield]

how can you adjust the fueling?

Remap or custom chip.

[gareth]

i just re read my posts and just to add, i'm not trying to p1ss on your fire, i'm an engineer and i work in insrumentation related jobs most i the time and i get pedantic about things like this

[reggid]

Simon,

do you have any more pics of this specifically where it draws air from in relation to ABS unit and radiator viewed from top sort of view?

I am thinking of using the top half found here http://rongineer.com/airbox.html with the bottom half as you have done.

I am not looking to alter the Alternator or PS but might have more flexibility for room given i don't have an AFM.

I don't have one in my hands to know where it will fit.

cheers

[Simon13]

Doug you will still have problems as the lower half of the air box takes it air from a more central location - where the rad is!

A facelift 2.5 radiator is in the way, A chrome bumper rad cures this, but the chromie cooling system wasn't as good as the late cars, plus the other dramas with the alternator

I mucked about with this the other day on my breaker car. You might* be able to make a bracket which spaces the whole air box up a touch, but the bottom of the box will still foul the alternator

[reggid]

Doug you will still have problems as the lower half of the air box takes it air from a more central location - where the rad is!

A facelift 2.5 radiator is in the way, A chrome bumper rad cures this, but the chromie cooling system wasn't as good as the late cars, plus the other dramas with the alternator

I mucked about with this the other day on my breaker car. You might* be able to make a bracket which spaces the whole air box up a touch, but the bottom of the box will still foul the alternator

thanks mate i have seen some other pics and its bigger than it looks, i wonder if the standard M3 lower section would fit easier?
I used to have a pic showing the difference but can't find it.

Or maybe the moulded top section by rongineer will fit a B25 lower half

[gooner1]

Interesting thread Si,what belt did you use in the end?

[Simon13]

i've never finished it to be honest. I never stuck it out to find a solution properly

I'd done the radiator and made some pipework for the the over flow. I then modded slightly an aircon bracket to mount the alternator on which held it fine, but it wasn't in line with the crank pulley. So the belt would be pissed

I've seen an M42 alternator which would be very close to what i'd want, but you'd have to extend the engine loom and find a way of tensioning the belt on the wrong side of the engine.

I still think its worth it if your mad enough to go through with it as i'm sure there is a good gain to be had as the dyno proved throughout the entire rev range in both torque and bhp

[reggid]

i've never finished it to be honest. I never stuck it out to find a solution properly

I'd done the radiator and made some pipework for the the over flow. I then modded slightly an aircon bracket to mount the alternator on which held it fine, but it wasn't in line with the crank pulley. So the belt would be pissed

I've seen an M42 alternator which would be very close to what i'd want, but you'd have to extend the engine loom and find a way of tensioning the belt on the wrong side of the engine.

I still think its worth it if your mad enough to go through with it as i'm sure there is a good gain to be had as the dyno proved throughout the entire rev range in both torque and bhp

I think the most gains with mine would be replacing the topsection though look like i might be able to get my hands on one.


There is some useful stuff if anyone else is interested

http://www.e30m3project.com/e30m3perfor ... irbox1.htm

[Simon13]

i thought it was the design of the whole airbox itself though.

They made it like it was to boost low/midrange torque on the S14. My logic was if it helped an S14 it should help an M20 or any other bmw lump which it seems to do in my brief test